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下文给大家带来Nginx是如何实现七层的负载均衡的，希望能够给大家在实际运用中带来一定的帮助，负载均衡涉及的东西比较多，理论也不多，网上有很多书籍，今天我们就用云在行业内累计的经验来做一个解答。
Nginx实现七层的负载均衡
调度到不同组后端云服务器
1. 动静分离
2. 网站进行分区
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拓扑结构
[vip: 20.20.20.20]
[LB1 Nginx] [LB2 Nginx]
192.168.1.2 192.168.1.3
[index] [milis] [videos] [p_w_picpaths] [news]
1.11 1.21 1.31 1.41 1.51
1.12 1.22 1.32 1.42 1.52
1.13 1.23 1.33 1.43 1.53
… … … … …
/web /web/milis /web/videos /web/p_w_picpaths /web/news
index.html index.html index.html index.html
一、实施过程
方案一 根据站点分区进行调度
http {
upstream index {
server 192.168.1.11:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.12:80 weight=2 max_fails=2 fail_timeout=2;
server 192.168.1.13:80 weight=2 max_fails=2 fail_timeout=2;
}
upstream milis {
server 192.168.1.21:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.22:80 weight=2 max_fails=2 fail_timeout=2;
server 192.168.1.23:80 weight=2 max_fails=2 fail_timeout=2;
}
upstream videos {
server 192.168.1.31:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.32:80 weight=2 max_fails=2 fail_timeout=2;
server 192.168.1.33:80 weight=2 max_fails=2 fail_timeout=2;
}
upstream p_w_picpaths {
server 192.168.1.41:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.42:80 weight=2 max_fails=2 fail_timeout=2;
server 192.168.1.43:80 weight=2 max_fails=2 fail_timeout=2;
}
upstream news {
server 192.168.1.51:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.52:80 weight=2 max_fails=2 fail_timeout=2;
server 192.168.1.53:80 weight=2 max_fails=2 fail_timeout=2;
}
server {
location / {
proxy_pass http://index;
}
location /news {
proxy_pass http://news;
}
location /milis {
proxy_pass http://milis;
}
location ~* \.(wmv|mp4|rmvb)$ {
proxy_pass http://videos;
}
location ~* \.(png|gif|jpg)$ {
proxy_pass http://p_w_picpaths;
}
}
方案二 根据动静分离进行调度
http {
upstream htmlservers {
server 192.168.1.1:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.2:80 weight=2 max_fails=2 fail_timeout=2;
}
upstream phpservers {
server 192.168.1.3:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.4:80 weight=2 max_fails=2 fail_timeout=2;
}
server {
location ~* \.html$ {
proxy_pass http://htmlservers;
}
location ~* \.php$ {
proxy_pass http://phpservers;
}
}
}
二、Keepalived实现调度器HA
注：主/备调度器均能够实现正常调度
1. 主/备调度器安装软件
[root@master ~]# yum -y install keepalived
[root@backup ~]# yum -y install keepalived
2. Keepalived
BACKUP1
[root@uplook ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id director1 //辅助改为director2
}
vrrp_instance VI_1 {
state BACKUP
nopreempt
interface eth0 //心跳接口，尽量单独连接心跳
virtual_router_id 80//整个集群的调度器一致
priority 100 //辅助改为50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
20.20.20.20
}
}
BACKUP2
3. 启动KeepAlived（主备均启动）
[root@uplook ~]# chkconfig keepalived on
[root@uplook ~]# service keepalived start
[root@uplook ~]# ip addr
到此：
可以解决心跳故障keepalived
不能解决Nginx服务故障
4. 扩展对调度器Nginx健康检查（可选）
思路：
让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Nginx失败，则关闭本机的Keepalived
a. script
[root@master ~]# cat /etc/keepalived/check_nginx_status.sh
#!/bin/bash
/usr/bin/curl -I http://localhost &>/dev/null
if [ $? -ne 0 ];then
/etc/init.d/keepalived stop
fi
[root@master ~]# chmod a+x /etc/keepalived/check_nginx_status.sh
b. keepalived使用script
! Configuration File for keepalived
global_defs {
router_id director1
}
vrrp_script check_nginx {
script "/etc/keepalived/check_nginx_status.sh"
interval 5
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
nopreempt
virtual_router_id 90
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass uplook
}
virtual_ipaddress {
192.168.1.80
}
track_script {
check_nginx
}
}
注：必须先启动nginx，再启动keepalived
调度到同一组后端服务器
网站没按业务/版块拆分，所有后端服务器提供整站代码。
=================================================================================
拓扑结构
[LB Nginx]
20.20.20.20
192.168.1.2
[httpd] [httpd] [httpd]
192.168.1.3 192.168.1.4 192.168.1.5
实施过程
1. nginx
http {
upstream httpservers {
server 192.168.1.3:80 weight=1 max_fails=2 fail_timeout=2;
server 192.168.1.4:80 weight=2 max_fails=2 fail_timeout=2;
server 192.168.1.5:80 weight=2 max_fails=2 fail_timeout=2;
server 192.168.1.100:80 backup; 等3、4、5 挂掉100上线
}
server {
location / {
proxy_pass http://httpservers;
proxy_set_header X-Real-IP $remote_addr;
}
}
}
2. Apache LogFormat 可选
LogFormat "%{X-Real-IP}i %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %b" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent
3. Nginx LogFormat
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